tests/kernel/test-hpet.c

   1 /* test-async-tsc.c
   2  *
   3  * test async tsc on AMD.
   4  */
   5
   6
   7 #include <asm/atomic.h>
   8 #include <linux/module.h>
   9 #include <asm/timex.h>
  10 #include <asm/hpet.h>
  11 #include <asm/io.h>
  12 #include <linux/clocksource.h>
  13 #include <linux/ltt.h>
  14 #include <asm/cacheflush.h>
  15
  16 //#define NR_LOOPS 10000
  17 #define NR_LOOPS 10
  18
  19 extern cycle_t read_hpet(void);
  20
  21 static int __init test_init(void)
  22 {
  23         int i;
  24         cycles_t time1, time2;
  25         volatile unsigned long myval;
  26         int sync_save;  /* racy */
  27
  28         sync_save = ltt_tsc_is_sync;
  29         ltt_tsc_is_sync = 0;
  30         //ltt_tsc_is_sync = 1;
  31         return -EPERM; //TEST !
  32         myval = ltt_get_timestamp64();
  33         time1 = get_cycles();
  34         for (i=0; i < NR_LOOPS; i++) {
  35                 //printk("time %llu\n", ltt_tsc_read());
  36                 //get_cycles_barrier();
  37                 //myval = get_cycles();
  38                 //get_cycles_barrier();
  39                 myval = read_hpet();
  40                 //clflush(&ltt_last_tsc);
  41                 //myval = ltt_get_timestamp64();
  42                 printk("val : %llu\n", (unsigned long long)myval);
  43         }
  44         time2 = get_cycles();
  45         printk("timediff %llu\n", (time2-time1)/NR_LOOPS);
  46         ltt_tsc_is_sync = sync_save;
  47         return -EPERM;
  48 }
  49
  50 static void __exit test_exit(void)
  51 {
  52 }
  53
  54 module_init(test_init);
  55 module_exit(test_exit);
  56
  57 MODULE_LICENSE("GPL");
  58 MODULE_AUTHOR("Mathieu Desnoyers");
  59 MODULE_DESCRIPTION("sync async tsc");
  60